Piston expander



March 5,1946. c. MELIDONI I 2,396,055

- :PISTON EXPANDER Filed Dec. 27; 1944- CONSTANTINE 'MELVIDOYNJI Patented Mar. 5, 1946 UNIED STATES PATENT OFFICE PISTON EXPANDER Constantine MelidonLfNew York, N. Y. Application December 27, 1944,'Serial No. 570,493

'10 Claims. (01. sea-12) i In the operation of engines it is found that piston metal. cannot withstand the terrific hammering and beating that a piston receives and hence the necessity for a scientifically designed skirt expander for the piston.

When installing piston skirt expanders known in the art, it is necessary to remove the piston and connecting rod from the engine, and the piston oii; the rod.

An object of this invention is to provide a piston skirt expander which can be installed while the connecting rod and the wrist pin is in assembled relation.

In theUnited States Patent No. 1,881,214, issued to me on October 4, 1932, I have disclosed a resilient piston having oppositely disposed resilient sections adapted to be independently expanded and I have provided resilient means disposed inside the body of the piston for expanding the resilient sections.

The resilient means for expanding the expandable sections of the piston skirt comprise,

springs housed within the piston and designed topress outwardly against the resilient skirt sections and thus moulding the resilient skirt sections and forcing them toassume thecontour of the. slightly larger sized circle. of the cylinder walls, and thus preventing piston slap.

In my said prior patent I have mounted the spring means directly at the center line of the wrist pin bosses. In my present disclosure the spring means also presses directly at the center line of the wrist pin bosses.

Another object of this invention is to provide a resilient expander having fourequal pressure sections in gripping engagement withthe skirt of the piston, the. expander floeing provided with hooks which are adapted to pass over the center line of the wrist-pin and whereby the expanderthe invention will be hereinafter more Darticu larly. described, and the combination and arrangement of parts will be shown in the accompin.

broken away'to show a central sectional portion and the piston skirt expander secured to the wrist Figure 2 is a plan view of the piston and skirt expander shown in Figurel.

Figure 3 is a vertical section view, the section being taken as on line 3-3" in Figure 1.

panying drawing and pointed out in the claims parts throughout the severalviews, in:

Figure 4 is a perspective View of the skirt expander with the clips in position and ready for. installing in a piston. c

Figure 5 is a perspective viewof the expander with the clips removed and with the loops expanded' into operating position.

In the illustrated embodiment of the inven-- tion, the numeral ill indicates a piston having its skirt .l..l vertically slotted at i2, i2 below the bottom piston groove 13. The skirt is also pro-- vided with a horizontal slot Hi extending between. the slots I2 and [2.

The horizontal slot i li approximately mid-- way between the piston pin bosses !5. The slotsv allow the piston skirt to contract and compensate forexpansion of the pistoncaused by heat in. the engine.

The piston skirt expander 51 is preferably formed of spring metal and is bent into substantially rectangular shape in plan view. The expander l1 comprises elongated sides. l8, each- 7 pressure sections 22, 22, 24, 24 assume a contour conforming to the inner circumference of the piston.

Ifhe ends of the. sides 18 have continuations 25, 25, extending toward the center line of thewrist pin bosses l5. The pressure sections 22, 22, 24, 24 are thus located directly at the center line of the wrist-pin bosses.

continuations 25' extending towards the center line of the wrist-pin bosses IS.

The ends 26 of the continuations 25' atthe sides l8 have horizontal portions 21 Whichterporn.

minate in hooks 28 which are designed to spring into engagement with a wrist pin 29 in the wrist pin bosses l5.

It will thus be seen that the loops IQ of the sides [8 are engageable with one side of the wrist-pin bosses I and that the hooks 28 are in resilient contacting relation with the wrist-pin 29 on the side opposite the loops l9.

It is to be noted that the body of the expander is preferably of square cross-section and that the hook portions 28 are flattened considerably to a rectangular cross-section to permit their entry between the connecting rod 30 and the wrist-pin bosses l5, where the clearance space is very slight.

In operation, the clips 20 initially contract the loops l9 and reduce the overall dimension of the expander I! to permit of its easy insertion into the piston skirt H.

When the expander is inserted into the piston and the hooks 23 are snapped over the wrist-pin 29, and with the pressure sections positioned in horizontal position, the clips 29 are removed and this causes the loops It] to expand and the expander to spring into operating position and cause the pressure sections to press firmly in opposite directions against the skirt.

In practice the expander IT has a range of expansion sufficient to take or coact with any size wrist-pin found in practice in pistons. One size expander only will take care of all piston pin diameters for any particular size of piston.

The four-point grip of the expander onthe skirt and the fact that the resilient expander hooks pass over the center line of the wrist-pin, insure that the expander will be resiliently mounted in fixed position within the skirt and adapted to withstand the vibrations to which the piston is subjected.

My one-piece expander is designed to expand opposite parts of the piston near the bosses l5 and without any necessity of slotting the piston. My expander is thus designed to operate in nonslotted pistons such as cast iron and steel pistons, which generally are not provided with slotted skirts. The pressure of the expander is sufficient to expand the skirt out of a true circle so as to contact worn cylinder walls at the bearing'sides of the piston.

While I have shown the loops as angularly positioned I may make expanders having loopswhich lie fiat on the wrist-pin bosses. I may also make expanders without any loops in the elongated sides.

My skirt expander is quickly and easily installed and machining of the piston or alteration of the piston is not necessary. The expander restores the original shape of the piston by exerting pressure against the collapsed thrust faces of the piston, that is, at right angles to the Wristpi it is not necessary to remove the wrist-pin or the connecting rod from the piston when installing the expander.

It is to be noted that the resiliency of. the hooks causes engagement with the wrist-pin so that the expansible hooks have a tendency of cushioning the play between the wrist-pin and piston bosses. The hooks are in forced gripping engagement with the pin and pull the pin against the inner surface of the wrist-pin bosses, thus avoiding any wristpin vibration.

It is further to be noted that my expander is designed to expand the piston at four independent sections, each two of which form concentric semicircles.

In accordance with the patent statutes I have described and illustrated the preferred embodiment of my invention, but it will be understood that various changes and modifications can be made therein without departing from the spirit of the invention as defined by the appended claims.

I claim:

1. A piston skirt expander formed of spring metal wire and adapted to be inserted into a split skirt of a piston having piston pin bosses and a piston pin, said expander having sides with expansible and contractible loops, the sides of said expander being engageable with one side of said bosses, said expander having ends lying in a circle when said loops are expanded, said ends being adapted to engage with inner surfaces of the piston skirt, said ends having continuations engageable with said piston pin.

2. A piston skirt expander formed of spring metal wire and adapted to be inserted into a split skirt of a piston having a wrist pin, said expander having sides with expansible and contractible loops and ends lying in a circle when said loop-s are expanded, said ends being adapted to engage with inner surfaces of the piston skirt, the sides of said expander being connected at one end and having two free and spaced-apart end portions at the opposite end, and continuations extending from said free end portions into encircling relation with said wrist pin.

3. A piston skirt expander formed of spring metal and adapted to be inserted into a split skirt of a piston having a wrist pin, said expander having elongated sides with expansible and contractible loops inclined toward each other and ends lying in a circle defining the inner contour of said piston when said loops are expanded, said ends beingadapted to engage with inner surfaces of said piston skirt, the sides of said expander being connected at one end and having two free and spaced-apart end portions at the opposite end, and continuations extending from said free end portions into'encircling relation with said wrist pin.

4. A piston skirt expander formed of spring metal and adapted to be inserted into a split skirt of a piston having a wrist pin, said expander having elongated sides with expansible and contractible loops, said loops being inclined toward each other, said expander having ends lying in a circle defining the inner contour of said piston when said loops are expanded, said ends being adapted to engagewith inner surfaces of said piston skirt, the sides of said expander being connected at one end and having two free and spaced-apart end portions at the opposite end, and continuations extending from said free end portions into hooked relation with said wrist pin.

5. A piston skirt expander formed of spring metal and adapted to be inserted into a skirt of a piston having a Wrist pin, said expander having elongated sides with expansible and contractible loops, said expander having four equal pressure sections lying in a circle defining the inner contour of said piston when said loops are expanded, said sections being adapted to engage with inner surfaces of said piston skirt, the sides of said expander being connected at one end and having two free and spaced-apart end portions at the opposite end, and continuations extending from said free end portions into hooked and resilient relation with said wrist pin.

6. A piston skirt expander formed of spring metal and adapted to be inserted into a skirt of a piston having wrist pin bosses and a Wrist pin, said expander having sides with expansible and V contractible loops and being enga eable with one having wrist pin bosses and a wrist pin, said expander having sides with expansible and contractible loops engageable with one side of said bosess, said expander having pressure sections defining the inner contour of said piston, the sides of said expander being connected at one end and having two free and spaced-apart end portions at theopposite end, and continuations r extending from said free end portions into 7. A one-piece piston skirt expander adapted to be inserted into the tubular body of a piston having wrist pin bosses and a wrist pin, said expander having sides with expansible and contractible loops, and engageable with said bosses, said expander having pressure sections contacting the inner contour of said tubular body, the sides of said expander being connected at one end and having two free and spaced-apart end portions at the opposite end, and flattened hook means extending from said free end. portions into resilient contacting engagement with said wrist'pin opposite said sides. V

8. A one-piece piston skirt expanderadapted to be inserted into the tubular body oi. a piston hooked and resilient contacting relation with said wrist pin on the side opposite said loops.

9. A piston expander of the character described, said expander having sides in engagement with wrist-pin and piston bosses and in-- tegral hooks opposite said sides and engageable with the wrist-pin for urging said Wrist-pin in the direction of the sides of said expander.

10. A piston expander of the. character described, said expander having sides' in engagement with wrist-pin and piston bosses and integral hooks opposite said sides and enga eable with the wrist-pin for urging said wrist-pin in the direction of the sides of said expander and serving to expand said piston at four independent sections, each two of which form concentric semi-circles.

CONSTANTINE MELIDONI. 

